Redirect single page

I use https://www.world4you.com as provider to host my wordpress installation which runs in a subdirectory.

My websites consists of only two pages: a one-pager which is the start (example.at) and the contact-info which is supposed to be example.at/contact-info.

I found this rewrite code in the documentation and it works perfectly for my landing page: example.at/subdirectory is rewritten perfectly to example.at

<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{HTTP_HOST} ^(www.)?example.at$
RewriteCond %{REQUEST_URI} !^/subdirectory/
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ /wp/$1
RewriteCond %{HTTP_HOST} ^(www.)?example.at$
RewriteRule ^(/)?$ subdirectory/index.php [L] 
</IfModule>

My problem is that I can’t figure out how I can get the permalinks or another rewrite rule to work, that the contact-info-sites is not shown as example.at/?page_id=1234 which is the case right now.

Can you guys help me? That would be awesome!